1. Oil

Figure 1.1 A modern oil-drilling ocean platform. Platform Holly, a few miles off the coast from Santa Barbara California, was installed in 1966 and has produced oil since. (Source: Linda Krop, Environmental Defense Center, Santa Barbara, CA)

Key facts

• Worldwide, people use about 30 billion barrels of oil a year, which works out to 210 gallons per person. The worldwide total is expected to increase to 50 billion barrels a year—350 gallons per man, woman, and child—in the next few decades.

• In 2005, the United States used 28% of all the oil consumed in the world.

• In recent years, the United States consumed about 7.5 billion barrels of petroleum a year, dropping to 7.1 billion barrels 2008 (23% of the world’s total consumption). More than 60% is imported; 17% of that is from the Persian Gulf.

• Two-thirds of all transportation energy in the United States comes from petroleum—2.2 billion gallons a day: 55% of this for ground transport of people, almost 36% for ground transport of freight, and just under 10% for air transport of both people and freight.¹

• According to conventional estimates, at the current rate of use Americans will run out of oil in less than 50 years.

It’s a stretch, but imagine you’re an Eskimo living 1,500 years ago

It’s around A.D. 500, and you’re part of a small group of Eskimos struggling northeast in Siberia near the Bering Strait and crossing by boat into what is now Alaska. There you find other Eskimo groups whose lives are a struggle—living at the margin, barely enough food, hard to do anything but try to keep warm and figure out where the next meal will come from. This was the life of most Canadian Eskimos at that time, a struggle for existence.

But according to anthropologist John R. Bockstoce, an expert on Eskimo culture and Eskimo and Yankee whaling, you and your Eskimo relatives coming from Siberia, called the Birnirk culture, brought with you inventions for hunting. One of these was a harpoon made of bone and antlers that, like a modern whaling harpoon, would slide closed into the flesh of the whale and then lock in an open position when the whale tried to swim away. Your group also had kayaks, umiaks, and drag-float equipment and began using these devices to hunt whales. This led to a fundamental change in your lives. Whale meat and oil gave you so much more energy than your neighbors that your group did much more than simply hunt and think about the next meal. With the basic necessities of life—food and shelter—assured, people could use their surplus energy and time in more enjoyable ways: telling stories, painting pictures, singing—in other words, being “civilized” in the modern sense. Or if they were concerned that their food supply might dwindle, they could use that excess energy and time to acquire more territory, more food, more power—in other words, to wage war.² The ability of early Eskimos to obtain meat and oil from whales is analogous to our ability to get petroleum cheaply and easily from the ground. As long as it was available that way, we could while away our leisure time with video games, golf, travel, and whatever else we wished. But by now almost everyone understands that petroleum is a finite resource that will be used up pretty soon if we continue to rely on it as one of our major sources of energy. Moreover, it’s equally clear that the use of petroleum, rather than declining, is going to increase, especially since the huge populations in China and India are rapidly increasing their ownership and use of automobiles.

Where does petroleum come from?

The fossil fuels—petroleum, natural gas, and coal—are just that, fossils. Coal was formed from the remains of trees and other woody plants, covered by soil and then buried deeper and deeper and subjected to heat and pressure, which converted their remains to mostly carbon, but with a fair amount of other elements that were part of the plants and the surrounding soil (for more on this, see Chapter 3, “Coal”). Petroleum and natural gas are believed to be the fossil remains of marine organisms.

All fossil fuels that we take out of the ground today were produced eons ago from the growth of photosynthetic organisms—algae, certain bacteria, and green land plants, organisms that can convert the energy in sunlight into energy stored in organic compounds, and do so by removing carbon dioxide from the atmosphere and releasing pure oxygen. The energy that fossil fuels contain is thus a form of solar energy, in most cases provided over many millions of years and stored since then.

Over time, much of the carbon from the carbon dioxide that algae, green plants, and some bacteria removed from the atmosphere was then sequestered—stored in the soils, rocks, and marine deposits, and prevented by various physical and chemical processes from returning to the atmosphere. When fossil fuels are burned, the sequestered carbon is released into the atmosphere as carbon dioxide (CO₂), which acts as one of the primary greenhouse gases.

Since petroleum and natural gas are not solids and thus are lighter than the rocks that surround them deep in the Earth (Figure 1.2), they tend to rise under pressure from the rocks and get trapped in geological pockets, like the one shown in Figure 1.3—although in some rarer situations the oil makes it to the surface, as it does in Southern California. Thus, the search for oil and gas is not random; petroleum geologists know which kinds of rock formations they are likely to occur in.

Figure 1.2 A typical location of oil and gas. Oil or gas rarely gets pushed right up to the surface, as it does at the La Brea pits in Los Angeles, famous for having trapped many ancient and extinct mammals whose fossils have become familiar. (Source: D. B. Botkin, and E. A. Keller, Environmental Science: Earth as a Living Planet. New York, John Wiley, 2009)

Figure 1.3 A natural oil seep along the California shore at Santa Barbara. Pressure from surrounding rocks has pushed petroleum up to the surface, where it flows into the Pacific Ocean, revealing itself by its bright reflection of sunlight. (Courtesy of the University of California, Santa Barbara, UCSB Map & Image Laboratory, from the research collection of Prof. Jack E. Estes)³

How much energy does petroleum provide?

In recent years, the United States consumed about 7.5 billion barrels of petroleum a year, dropping to 7.1 billion barrels 2008. More than 60% of petroleum is imported; 17% of this from the Persian Gulf.⁴ Petroleum provides about 37% of the world’s energy and 41% of the energy used in the United States,⁵ most of which is used for transportation. The United States alone uses 8.4 billion barrels of oil a year. According to the U.S. Department of Energy, essentially all the energy used in transportation in the United States comes from fossil fuels,⁶ and two-thirds of all transportation energy in the United States comes from petroleum: 2.2 billion gallons a day—55% (1.2 billion gallons a day) for ground transport of people, almost 36% (789 million gallons a day) for ground transport of freight, and just under 10% (210 million gallons a day) for air transport of both people and freight.⁷ In contrast, petroleum provides only 1% of the electricity produced in the United States.⁸ Most electricity in the United States is produced from coal, hydropower, and nuclear power. To keep things simple, think about petroleum as the transportation fossil fuel.

How much petroleum is there, and how long will it last?

These are straightforward questions, so one might expect them to have straightforward answers. Don’t petroleum geologists and oil corporations know how much oil is in the ground, how much they can sell in a year, and therefore how long oil will last? Wouldn’t this be a basic part of an oil company’s business plan?

Unfortunately, it’s not that simple. As economists and petroleum geologists will tell you, there is always more in the ground than you can get out, and the percentage you get out depends on how hard you want to work, or how much you are willing to pay, to get it. When oil was very, very cheap, around the first decades of the 20th century, it wasn’t worth much to develop new technologies to get every last drop when the initial gusher and subsequent flow eased and the oil no longer flowed freely out of the ground. Today, we have many ways to push more of the underground oil to the surface or separate it from the rocks that hold it. So the answer to how much oil is in the ground is: It depends on what you are willing to pay.

As to the second question—how long will Earth’s petroleum last?—economists will tell you that rather than being drained to the last drop, petroleum will eventually become so rare and so expensive to get out of the ground that it will no longer be useful as fuel. People may collect it, the way they collect other precious minerals, and display little jars of the black goo on their coffee tables as decorations and as evidence of their wealth. The real question therefore is not when every drop of oil will be gone but when it will no longer be economically worthwhile to extract it.

What will raise the price of oil and thereby make it worthwhile to try harder and harder to get it? One standard answer is that the price of oil will rise rapidly when peak production is reached—that is, when discovery of new oil declines. Another economic turning point is when the rate of supply drops significantly below the demand.

As petroleum reserves shrink, they get harder and harder to find

We’re using more and more petroleum and finding less and less of it. Indeed, petroleum geologists suggest that we’re going to run out of petroleum in the next few decades. History seems to be on the side of this viewpoint. In 1940, five times as much oil was discovered as consumed. Forty years later, in 1980, the amount of petroleum discovered just about equaled the amount consumed. And by the turn of the 21st century, world consumption of petroleum was three times the amount that was discovered.⁹ Based on this history and our knowledge of the kinds of rocks where petroleum can be found, it seems likely that oil production in the United States will end in 50 years or at least by the end of this century, and world oil production soon after.

To understand how petroleum geologists think about these things and make calculations, you first need to understand the terms resources and reserves. A petroleum resource is the oil that can be extracted economically. A reserve is part of the resource, the part that, at the time it is evaluated, is judged to be eventually extractable both legally and economically. Proven reserves are those that have been determined to be legally and economically extractable right now. (The proven reserves idea leaves open the possibility that as prices for petroleum rise, it may become economically worthwhile to extract oil from reserves that are now considered too costly to use.)

Today, petroleum geologists estimate that the world’s proven reserves are 1 trillion barrels (42 trillion gallons), and that total reserves—oil that eventually will be legally and economically accessible—are probably 2–3 trillion barrels. These estimates are based on a lot of geological knowledge as well as the location and size of existing oil wells. In fact, there is a wide range in the estimates of how many barrels of oil are now or soon will be considered proven reserves. For example, the U.S. Energy Information Administration reports values from 1–4 trillion barrels.¹⁰

In predicting when the oil supply will become a serious problem, petroleum geologists focus on the peak oil point—the time when one-half of Earth’s oil has been exploited. This is usually projected to occur sometime between 2020 and 2050, although a variety of experts believe it has occurred already in the United States. The time of peak oil production is important because we can assume that when that point is reached, the price of oil will rise rapidly. The Energy Information Administration presents a range of estimates for the time of world peak oil production, from as early as 2020 to as far into the future as 2121.¹¹

The implications are huge about how much time this gives the nations of the world to prepare for a planet without petroleum. Given the way most people and societies go about planning for events that they hope won’t occur until far in the future, it seems likely that if peak oil production is expected to occur a century or more from now, little will be done to move away from fossil fuels in the next year or even the next decade, and when the time comes we’ll all just muddle through. This will be unfortunate, because moving away from petroleum (and the other fossil fuels) is a good idea for reasons other than direct energy supply. For example, we could stop worrying about international conflicts over oil, avoid direct pollution from toxins given off by petroleum, and reduce the release of greenhouse gases. Those who place a high priority on a healthful, pleasant, and sustainable environment would therefore prefer to be told that peak oil is almost upon us, so that nations will be spurred to action.

For a more straightforward estimate of when the world will run out of petroleum, here are some numbers. Worldwide, people use about 30 billion barrels of oil a year (210 gallons a year per person). Conservatively—not taking into account the maximum potential increase in automobiles in China and India—worldwide consumption is expected to rise to about 50 billion barrels a year by 2020, which means that the whole world will use up today’s proven petroleum reserves in about 20–40 years and use up the total estimated reserves in about 60 years. Since not all our many uses of petroleum may be readily adaptable to other fuels, this puts a lot of time pressure on all nations to get something going quickly to replace petroleum, especially for transportation.

However, there is another point of view, which is that conventional petroleum geologists greatly underestimate both the available amount of petroleum and how efficiently oil can be gotten out of wells. This viewpoint was well expressed in the Wall Street Journal op-ed piece titled “The World Has Plenty of Oil,” by Nansen G. Saleri, president and CEO of Quantum Reservoir Impact, in Houston, and former head of reservoir management for Saudi Aramco.¹²

Mr. Saleri says that present oil mining technology gets only one-third of the oil out of a well; the rest clings to the rocks and is just held too tightly for current pumping methods to get it out. “Modern science and unfolding technologies will, in all likelihood, double recovery efficiencies,” he writes. “Even a 10% gain in extraction efficiency on a global scale will unlock 1.2–1.6 trillion barrels of extra resources—an additional 50-year supply at current consumption rates.”¹³

Mr. Saleri argues that rising prices for petroleum will fuel technological development that will increase extraction efficiency. Two major oil fields in Saudi Arabia are already yielding two-thirds, rather than one-third, of the oil out of the wells. Mr. Saleri writes that the total resources are 12–16 trillion barrels, not the 1 to 3 trillion barrels of conventional estimates, and that 6–8 trillion of these total resources are in conventional wells, the rest in “unconventional” sources, shale oil and tar sands, from which it is difficult and environmentally costly to get oil. Present attempts to recover oil from these unconventional sources are disrupting and polluting land (more about that later). Even with his optimistic assumptions, he estimates that peak oil production will be reached between 2045 and 2067—in 38–59 years.

Geography is against us

Unfortunately for most of us, petroleum reserves are not distributed evenly around the world. Quite the opposite; they are highly concentrated (Figure 1.4) and, worse yet, concentrated in parts of the world that, on the whole, are not the ones that use the most petroleum today but will likely require more in the future (Figure 1.5). The Middle East has 62% of the world’s oil reserves (Figure 1.6); the rest of Africa 9.7%; South and Central America 8.6% (most of it in Venezuela and Brazil); the Russian Federation 6.6%. North America has just 5%, half of it in the United States.¹⁴ So, as Figure 1.4 makes clear, oil reserves are extraordinarily concentrated geographically.

Figure 1.4 The world’s known oil reserves (2006).¹⁵ (Source: BP Statistical Review of World Energy, June 2007; London, British Petroleum Company)

Figure 1.5 Oil consumption per capita (metric tonnes, 2006). Compare the consumption with known reserves. (Source: BP Statistical Review of World Energy June 2007; London, British Petroleum Company)

Figure 1.6 Middle Eastern nations have 62% of the world’s available oil. Most of this is in five nations: Saudi Arabia (with more than 20%), Iran, Iraq, Kuwait, and the United Arab Emirates.¹⁶

It would be naive to think that the lopsided geographic distribution of petroleum will not continue to create international conflicts. As long as the United States and other countries without vast oil reserves continue to depend so heavily on petroleum, these conflicts are likely to increase, which is all the more reason to turn to other sources of energy as soon as possible.

Although the Middle East dominates world oil reserves, most of that oil goes to Europe, Japan, and Southeast Asia, whereas the United States imports a lot of oil from Canada, Mexico, and Venezuela (Figure 1.7). Obviously, the more oil the United States imports, the more vulnerable its economy is to the reserves in other nations and to political and environmental events that limit or prevent this importation. Given the importance of abundant energy for a vibrant economy and society, greater energy independence is an important goal, but for petroleum this is not and will not be possible for the United States.

Figure 1.7 Where the United States gets its oil. (Source: Energy Information Administration, 2008)¹⁷

Where might new oil reserves be found?

Recent discoveries of oil have been primarily in the Middle East, Venezuela, and Kazakhstan.¹⁸ Ironically, global warming may change this, since less ice in the Arctic may mean more opportunities for oil exploration where it was difficult before. Also, while at present drilling for oil in Arctic waters is mostly limited to a depth of 300 feet and in some cases 2,000 feet, new ships will make it possible to drill for oil in water 12,000 feet deep.¹⁹ One estimate suggests that 400 billion barrels of oil may be found in the Arctic oceans.²⁰

Although this is a lot of petroleum, at current rates of use it would add only eight years to the time we have before the world runs out of oil.²¹ And there’s a potential downside: More global warming provides more sources of oil—for example in the Arctic, which produces more greenhouse gases, which lead to more global warming.²² Then, too, there is already plenty of concern about oil spills and their effects on ocean ecosystems, sea and shore birds, and fisheries, and the ability to drill much deeper in a much larger area increases the risk of drilling-caused spills.

Two unconventional sources of oil: oil shales and tar sands

As explained earlier, petroleum under pressure from underground rocks fills pockets in the rocks. But in addition, some muds trap petroleum as they form into shales, resulting in a dense rock filled with oil. The oil is tightly bound within the rock and can be released only if the shale is heated to 900°F. At this temperature, a ton of shale may yield as much as 14 gallons, and three tons of shale would be needed for each barrel of oil. Heating three tons of rock to 900° takes a lot of energy and leaves behind a lot of crushed rock. Much of this rock is obtained from surface mines, and even more energy is needed afterward to restore the damaged land—restore it as much as possible, that is. Not only are oil shales a highly polluting energy source, destructive to the land, but also their net energy yield is low compared to conventional sources of oil.

Tar sands (sometimes also called oil sands) are geologically similar to oil shales, but the petroleum impregnates sand or clay rather than mud. Again, the petroleum is so completely mixed with the inorganic material that one can’t pump the oil out. The sand has to be mined, primarily by strip mining, and then washed with hot water. As with oil shales, a mess remains—in this case dirty water as well as tons of sandy rock. Tar sands are said to yield as much as one barrel for about every two tons processed.

Those who believe there is a lot more oil out there than 1–3 trillion barrels are basing their estimates partly on what could be gotten from oil shale and tar sands. An estimated 3 trillion barrels of oil exist in oil shales and about the same in tar sands. Together, these massive but difficult-to-use sources could triple the amount of oil available, if all of it could be recovered.

Much of the world’s known tar sands and oil shales are in North America. The United States has two-thirds of the known world oil shale, and it is estimated to contain 2 trillion barrels of oil. Some 90% of U.S. oil shale is in the Green River formation underlying parts of Colorado, Utah, and Wyoming and extends over 17,000 square miles, an area larger than Maryland.²³ Canada has an estimated 3 trillion barrels of oil in tar sands, most of it in a single huge area near Alberta now called the Athabasca Oil Sands. Since so much energy is required to get the oil out of these rocks, the net yield would not be nearly as great as from conventional oil wells. Still, the government of Alberta states that tar sands yield six times the amount of energy required to process them.²⁴

Oil shales and tar sands are already causing major environmental controversies, since so much oil exists in them, and since mining and refining it are so polluting. Mining the 2 trillion barrels of petroleum from U.S. oil shales would leave behind 9 trillion tons of waste rock—an amount equal to the weight of 24 million Empire State Buildings. To put this into perspective, in 2007, all the freight transported in the United States weighed 21 billion tons. So it would take all the freight transportation available in the United States about 424 years to move that much waste rock.²⁵

Three tar sands mines are operating today: Suncor (opened in 1967), Syncrude (since 1978), and Muskeg River of Shell Canada (opened in 2003). They are producing 1 million barrels a day²⁶ and have affected 120 square miles.²⁷ Mining Athabasca Oil Sands takes 2.2 to 5 barrels of water for every barrel of oil.²⁸ Water used for this processing comes from the Athabasca River, which starts in the beautiful Canadian Rockies as the outflow from the Athabasca Glacier. The government of Alberta states that only 3% of the average annual outflow of the glacier is required to process the sands,²⁹ but environmental groups estimate that it will require a quarter of Alberta’s freshwater.³⁰ This water would end up in holding ponds, contaminated by toxic chemicals from the mining and processing: mercury, arsenic, and a variety of organic compounds that are carcinogenic.³¹

Effluents from present tar sand operations are being blamed for human and wildlife ailments,³² and the holding ponds present an even greater hazard. According to Professor David Schindler of the University of Alberta, a leading aquatic ecologist, “If any of those tailings ponds were ever to breach and discharge into the river, the world would forever forget about the Exxon Valdez.”³³

Currently, oil production from Athabasca Oil Sands costs between $15 and $26 a barrel, compared with about $1 per barrel from Saudi Arabia’s wells. But when oil prices exceeded $130 a barrel in 2008, mining those tar sands began to sound like economic sense—except for the pollution (at the time of this writing, oil is $72 a barrel).

Oil shales are not yet in commercial development, but Shell Oil Corporation has invested many millions of dollars in attempts to develop this petroleum source.³⁴ The near future will bring a major battle over North American tar sands and oil shales since they offer huge profits at great environmental costs.

Growing worldwide competition for a dwindling resource

International competition for petroleum is growing, in large part because rapidly rising standards of living in India and China are leading to a greater number of automobiles. India now has 5.4 million vehicles, up 500% in just 20 years.³⁵ China has 34 million registered motor vehicles.³⁶ In 2006, sales of personal autos rose 30% in China, to 5.8 million,³⁷ and China’s total vehicle sales reached 7.22 million. To put this into perspective, this is close to half the number of cars sold in the United States in 2007 (about 16 million).³⁸ In 2003, China became the world’s fourth-largest automobile-producing nation, behind only the U.S., Japan, and Germany.³⁹ This increased competition alone is enough to push petroleum prices up. And they’re going to go even higher. The cost of generating electricity with oil (and with natural gas) in the United States has been rising sharply. Domestic electricity cost 20% more in 2006 (the most recent date for which data are available) than in 1995.⁴⁰

If supplies are dwindling, why watch petroleum go up in smoke?

On May 15, 2007, the Wall Street Journal reported that Aramco, a highly profitable state-run Saudi oil giant, had signed a huge deal with Dow Chemical. Why would the world’s largest producer of fuel oil be interested in making a deal with a chemical company? Since petroleum is an excellent base for many artificial chemicals, a large number of very popular and very profitable products—including most plastics—that most of us would be unwilling to do without are made with them. According to the Wall Street Journal, the Aramco-Dow agreement is supposed to lead in 2013 to a joint venture that will build plants to produce 7 million tons a year of these chemicals.⁴¹ And by the end of May 2008, Dow Chemical announced that it would have to raise the price of its petrochemicals 20% because of the rising price of crude oil.⁴² Why waste whatever petroleum we have left by burning it all up fast as fuel? Why not use alternative energy sources and save petroleum for other important purposes that use much less of it?

Environmental effects of petroleum

Petroleum causes pollution at every stage, from mining and recovery to refining, transporting, and using it as fuel. Drilling wells can cause direct pollution via oil spills. Drilling also often involves injecting watery liquids into the wells; later released as drilling muds, these cause their own toxic pollution.

The notorious Exxon Valdez oil spill taught us that transporting oil by tanker ships can lead to disaster. Transporting oil by pipeline or truck can also lead to spills, because pipes break and trucks sometimes have accidents.

Crude oil—oil as it comes out of the ground—is many chemicals mixed together, and these must be separated into gasoline, kerosene, diesel fuel, heating oil, and heavier materials. This is what a refinery does: Like a giant chemistry set, it heats crude oil and separates its chemicals according to their density. The strong odors that make passersby wrinkle their noses are petroleum chemicals that the refinery has released into the environment—chemical pollutants. Travelers nearing the end of the New Jersey Turnpike on their way to the tunnels into New York City know exactly what I’m talking about.

These are just an indication of the potential for refineries to leak chemicals into the air, soil, and groundwater; to suffer accidental fires and breakages that produce more pollution; and to create sites that are heavily toxic for future generations.

Effects of the Exxon Valdez Alaskan oil spill are still with us

On March 24,1989, the tanker Exxon Valdez spilled 10.8 million gallons of crude oil into Prince Edward Sound, Alaska. Although it was not the largest spill ever, the oil slick extended over 3,000 square miles and inflicted heavy damage. The wildlife affected have been estimated to include 250,000 to 500,000 seabirds, at least 1,000 sea otters, about 12 river otters, 300 harbor seals, 250 bald eagles, and 22 killer whales.⁴³ Nearly 19 years later, the spill still affects Alaska’s fisheries, and lawsuits over its effects include the Alaskan Eskimos’ $2.5 billion suit for damages.⁴⁴ Costs of this kind are not usually counted in tallying the total costs of petroleum.

Petroleum exploration versus conservation of endangered species

The Arctic National Wildlife Refuge is a classic example of the conflict between the search for more petroleum and the conservation of wildlife and endangered species. The refuge is in beautiful country. It was established in 1960 and expanded in 1980 to cover 19 million acres, larger than the combined area of Massachusetts, New Hampshire, and Vermont (Figure 1.8, top). It is the primary breeding ground for 123,000 caribou of the Porcupine herd (named for the Porcupine River [Figure 1.8, bottom]) and is also a major wintering ground for this population.

Figure 1.8 Map of Alaskan National Wildlife Refuges (top). Each dark area is a refuge. The Arctic National Wildlife Refuge, the one discussed in this book, is listed as “Arctic” at the top right. Caribou within the refuge (bottom). (Courtesy of the U.S. Fish & Wildlife Service: http://arctic.fws.gov/caribou.htm. See also http://arctic.fws.gov/pdf/ispch.pdf)

The refuge also contains an estimated 10 billion barrels of oil. How much of this could be recovered is uncertain—conservative estimates are about 3 billion barrels. The possibility of drilling for oil in the refuge was remote until the 21st century; the George W. Bush administration pushed for it, arguing that it would help make the United States more energy-independent. But the United States has been using about 7.5 billion barrels of oil a year, so at best all the oil in the Arctic National Wildlife Refuge would buy the U.S. less than a year’s worth of oil. At the time of this writing, neither the Obama administration nor Congress has made any decisions about drilling there.

Here are some of the other ways that petroleum pollutes. Burning petroleum pollutes the air, creating health problems and damaging plants and wildlife. Among the primary petroleum-generated air pollutants are ozone, nitrogen oxides, and particulates. Also, pipelines and storage tanks leak. In 2001 a rifle bullet punctured the Trans-Alaska Pipeline, resulting in a small but nonetheless damaging spill. Among the good news is that although the 2002 Alaska earthquake ruptured the earth under the pipeline, the line stayed intact.

The bottom line

• Known petroleum sources will run out in less than 50 years (according to conventional analysis) or perhaps in 100 years or so (unconventional analysis).

• Whatever the exact time when petroleum runs out, we have a choice: We can devote a large portion of our time, resources, and energy to seeking new oil and improving extraction efficiency, or we can seek sustainable and cleaner energy sources.

• Petroleum is one of the three most polluting energy sources (the other two are nuclear power and coal). The potential for pollution will increase as conventional oil sources run out and the world turns to the unconventional sources: tar sands, oil shales, and deep ocean drilling.

• In an ideal world, the search for new energy sources would move away from petroleum, but so much money can be made from obtaining and selling crude oil that oil development will likely continue in the short term despite increasing pollution and increasing knowledge of its health and environmental effects.